A plurality of wellbores may be drilled from a single position, for example from an offshore drilling platform. A first wellbore may be drilled and a casing set in the first wellbore. Thereafter a window may be cut in the casing at a location for initiating a lateral wellbore and a lateral junction may be placed in the window.
To initiate a lateral wellbore, a drilling deflector tool, for example a first whipstock, may be attached to a workstring and run-in during a first trip into the wellbore and set at a first position for deflecting a cutting tool into the casing to cut the window and initiate the lateral wellbore. The workstring may be withdrawn during a first trip out of the wellbore. A cutting tool may be attached to the workstring and run-in during a second trip into the wellbore and the window cut in the casing. The cutting tool may then be withdrawn during a second trip out of the wellbore. A retrieval tool may be attached to the workstring and run-in during a third trip into the wellbore to couple to the drilling deflector tool. The retrieval tool and the drilling deflector tool may then be withdrawn during a third trip out of the wellbore. A completion deflector tool, for example a second whipstock, may be attached to the workstring and run-in during a fourth trip into the wellbore and set at a second position for deflecting a completion tool into the window. The workstring may then be withdrawn during a fourth trip out of the wellbore.
A completion tool may be attached to the workstring and run-in during a fifth trip into the wellbore. The completion tool may be set in the window, for example establishing a lateral junction. The completion tool may be a screen or some other contrivance to prevent undesired entrance of solids and/or fluids from a formation proximate to the window into either the wellbore or the lateral wellbore. The junction may be in conformance with one of the levels defined by the technology advancement for multilaterals (TAML) organization, for example a TAML Level 5 multilateral junction. The workstring may be withdrawn from the wellbore during a fifth trip out of the wellbore. A drilling tool may be attached to the workstring and run-in during a sixth trip into the wellbore. Drilling in the lateral wellbore may then be continued.
In some drilling environments, for example offshore drilling platforms located in the North Sea and/or off the coast of Australia, operating costs of drilling rigs may be in the range from $500,000 per day to over $1,000,000 per day.